Wheel springing element



Ammo, 194s. 'E.'H.PIRON 1 2,4393% WHEEL SPRINGING ELEMENT Filed March 29 1943 .2 Sheets-Sheet l E. H. PIRON WHEEL SPRINGING ELEMENT April 20, B948.

2 Sheefs-Sheet 2 I I n A 'EMIL H-P/ Filed March 29, 1943 Patented Apr. 20, 1948 WHEEL SPRINGING ELEMENT Emil n. Piron, New York N. r.,

ssi n Transit Research Corponfiion, New York,

or to N. Y.,

a corporation of New Yor Application March 29, 1943, Serial No. 480.998

6 Claims. (01. 295-11) This invention relates to springing elements for resilient wheels and has for its object to provide elements which will give substantial deflection under radial wheel loading and which will have prolonged life.

Many present day resilient wheels employ springing elements each comprising a comparatively thick toroid of rubber having metallic discs surface bonded to opposite faces thereof. If the peripheral surfaces of those toroids were cylindrical the rubber would bulge at their inner and outer edges under the pressures required by assembly, to such an extent that serious tension would be set up. In an attempt to obviate the cracking of the bulging edges which results from this condition the peripheries of the toroids are rooved on acurve such that when the pressure of assembly is imposed the peripheral edges assume a cylindrical shape. This solution has not proven entirely satisfactory with increasingly thicker rubbers as cracking still occurs along the edges due to the high local strains and stresses under high operating pressures with the result that while the life of the rubber was materially lengthened, it becomes increasingly desirable and, in fact, essential at this time that these rubbers be given greater life.

The principal object of this invention is to provide mating rubber springing elements which will have a deflection equal to that found satisfactory in the present day wheels and which are so constructed that the tendency to crack at the inner and outer periphery will be largely overcome.

A further object is'to provide a method of making theseimproved elements, commonly known as wheel sandwiches by virtue of the rubber being sandwiched b .ween two metallic plates.

In carrying my invention into eil'ect I provide a mold capable of holding three metallic plates in spaced relation with rubber filling the spaces between the plates. The mold with its charge is then subjected to heating in order to vulcanize the rubber and to cause it to bond to the plates. The article is then removed, the center plate is ground or sheared to size as may be necessary and one springing element is ready for use. The term rubber will be understood to mean natural 71' synthetic rubber and also any synthetic material possessing rubber-like characteristics which render it suitable for use as a springing medium.

The invention will be better understood with reference to the accompanying drawings in which Fig. 1 is a diametric section through a mold coded with rubber separating three metallic plates, of which the center plate is maintained the line i-l Fig. 2,

openings in the outer plates, ready for heating to form my improved wheel sandwich, taken along Fig. 2 is a. top plan view of the mold of Fig. i

.with the top of the mold removed to show an outside metallic plate and the periphery and vicinity of the central plate,

Fig. 3 shows diametric views of the elements after removal from the mold, taken centrally through the scallops, along the line 3-3 of Figure 1, Figure 3A when dowels are provided at one side and Fig. 313 where dowels are provided at both sides, and

Fig. 4 is a diametric section through a wheel employing my improved elements as shown in Fig. 3A and fully assembled.

More particularly, a mold is provided composed of two parts i and 2 each having a major cavity of the same size and shape, each cavity having the shape of a cylinder with scalloped sidewalls to conform to the shape of the disc 5 as shown in Fig. 2. The part I also has a secondary cavity portion 3 formed by removing a portion of the surface which contacts the other mold part 2. The bases of the cavities in the parts i and 2 receive metallic discs t and 5 respectively, in close fitting engagement therewith. An unvulcanized mass of rubber is then placed against the disc ll, another unvulcanized mass of rubber l is placed against the disc 5, and a third disc 3 is placed over the mass 3. The mold part 2 with its charge is then closed ,on the part i with the mass 1 lying against the disc t.

It will be noted that the two discs t and t have large central openings threthrough. The disc 8 has a. central opening therethrough of less diameter than that of the other two discs and also smaller than the core of the mold. The outer periphery of the disc t is cylindrical and its diameter is greater than the greatest diameter of the discs 6 and W, the outer peripheral portion 9 thereof occupying the secondary cavity 3 of the mold part i and its inner peripheral portion, 9a, part of the space between the cores of the mold. The portions 9 and as thus hold the disct equally spaced between the bottoms of the large cavities in the mold parts i and 2. In addition, mold dowels ll project from recesses in the bottom of each part i and 2 of the mold and extend through holes provided in the two outer plates 4 and 5, to the corresponding surface of the inner plate 8, thus helping to maintain the plate 8 in position.

Alter the mold is closed it is then subiected to heat for a suiilcient time to vulcanize the rubbers i and i which bonds the rubber to the discs 4, and I. it being understood that these discs will have been brass plated or otherwise prepared so that good surface-bonding will take place.

The resultant product is then removed from the mold,-the pins ll removed and, if necessary, the disc 2 is ground or sheared to the proper size and shape. In preierred'form the peripheries of the disc 8 are left as they come from the mold to avoid the expense and complications of trimming. The springing element thus formed is as illustrated in F18. 3A. This figure and Figure 2 also illustrate that hollow dowels it are provided in disc I, these dowels being pressed from the disc prior to insertion in the mold. The dowels become partially filled with rubber as the mold is charged and as vulcanization proceeds. the pins ll occupying the remaining space.

The mold part I has small cavities in its base equal in size and number to the small cavities in the base of the mold part 2 which receive the dowels It and .the outer ends of the pins ii. However, the plates 4 are not provided with dowels corresponding to dowels it but with holes which are covered by small plates i2, the plates 12 each having a hole therethrough through which a dowel pin it extends. After removal of the pins ll openings it remain.

Figure 3B shows a springing element made from the same mold in which the small plates l2 have been removed. Dowels Ma are formed'on the plate 40. in the same manner as on the plate to, these being identical with the dowels Ill of plate I. Pins H are used during vulcanizing and the resultant springing element is the same on both sides, as illustrated. It will also be noted that scallops 25 which are formed in the plate 5 are also formed in the plates 4a and 5a. This diflers from the plate 4. the outer periphery of which is continuously circular and is provided with bolt holes 26 in alignment with the center line of the corresponding scallops.

The springing elements are now ready for assembly in a wheel. The assembly is illustrated in Fig. 4 in which i4 indicates a wheel hub havin a plate J5 radiating outwardly therefrom and fixed thereto. A second plate It is bolted to the end of the hubs I4 and i1 and radiates from the axis of the hub I4, thus being parallel to the plate It. The tire or tread surface i8 has a plate It radiating inwardly therefrom and residing between the plates and It. The plate It has a central opening 20 therethrough substantially larger than the outside diameter of the hub to permit relative movement therebetween. Between the tire is and the opening 20 are openings 2! through which assembly bolts 22 pass, these openings being substantially larger than the diameter of the bolts to permit relative movement therebetween.

In making the wheel assembly the springing element as shown in Fig. 3A is illustrated. It is placed against the plate ii, the bolts 22 then screwed into the plate It with their shoulders 23 pressing the plate 4 firmly against the plate It. The plate it which has dowel holes is then placed against the doweled side of the springing element. Another similar springing element is.

then placed against the plate I! with its dowels l0 fitting into'the dowel holes in the plate. The openings 28 in the disc 4 receive the threaded outer ends of the bolts 22, the bolts each being provided with an enlarged shoulder 24. The

shoulders 23 and 24 act as spacers. The outer plate It is then placed against the plate 4 and nuts 25' threaded on the outer ends of the bolts 22. The bolts 22 thus act as dowels to prevent relative sliding movement between the plate It and the disc l2.

Where the element illustrated in Fig. 3B is used the outer plates l5 and It will also be provided with dowel holes similar to those dowel holes found in the plate It. It is also feasible, in the same wheel, to use one element as illustrated in Fig. 8A and the other as shown in Fig. 33.

Various changes will occur to those skilled in the art and I desire to be extended protection within the scope of the appended claims.

- What I claim is:

1. As an article of manufacture, a springing element for a resilient wheel composed of three side by side metallic discs each having a central opening therethrough, the outer discs being adapted for direct attachment to the hub and rail contacting member respectively of the wheel having identical inside, outside diameters and the inner disc being adapted to float between said outer discs and having a larger outside and a smaller inside diameter than said outer discs, and a mass of rubber-like material equal in inside and outside diameters respectively to the outer metallic discs separating the inside disk irom each of said outside discs.

2. As an article of manufacture, a springing element for a resilient wheel composed of three side by side metallic discs each having a central opening therethrough, the outer discs having identical inside and outside diametersvand the inner disc having a larger outside and a smaller inside diameter, and a mass of rubber-like material separating the inner plate from each of the two outer plates, the inside and outside diameter of both masses of rubber-like material being equal to the inside and outside diameters respectively of the outer metallic discs, at least one outside disc having hollow dowels projectin from the outside surfaces thereof;

8. As an article of manufacture, a springing element for a resilient wheel composed of three side by side metallic discs each having a central opening therethrough, the outer discs being adapted for direct attachment to the hub and rail contacting member respectively of the wheel having identical inside and outside diameters, the inner disc being adapted to float between said outer discs and having a larger outside and a smaller inside diameter than said outer discs and a mass of rubber-like material separatins the inner plate from each of the two outer plates the inside and outside diameter of both masses oi rubber-like material being equal to the insid:

and outside diameters respectively of the cute! metallic discs, said inner and one of the OlltSldi discs being scalloped at their outer peripheries said masses of rubber also being correspondingli scalloped.

4. As an article of manufacture, aspringing element for a resilient wheel composed of threl side by side metallic discs each having a centre opening therethrough, the outer discs havin! identical inside and outside diameters and th inner disc having a larger outside and a smalle inside diameter, and a mass of rubber-like ma terial separating the inner plate from each 0 the two outer plates, the inside and outside diam eter of both masses of rubberelike material helm equal to the inside and outside diameters respec tively of the outer metallic discs, one outsid disc and the inside disc each being scalloped at their outer peripheries, the remaining disc having a circular outside periphery and being pierced inwardly of its outer periphery at points opposite the scallops in the other two discs.

5. As an article of manufacture, a springing element for a resilientwheei composed of three side by side metallic discs each having a central opening therethrough the outer discs having identical inside and outside diameters and the inner disc having a larger outside and a smaller inside diameter, and a mass of rubber-like material separating the inner plate from each of the two outer plates, the inside and outside diameter of both masses of rubber-like material being equal to the inside and outside diameters respectively of the outer metallic discs, the inside disc and one outside disc being scalloped at their outer periphery, the other outside disc having a circular outer periphery, both of said masses of rubber-like material being scalloped to correspond to the scallops of said discs, said other outside discs being pierced to correspond to said scallops.

6. As an article of manufacture, a springing element for a resilient wheel composed of three side by side metallic discs each having a central.

opening therethrough the outer discs having identical inside and outside diameters and the inner disc having a larger outside and a smaller inside diameter, and a mass of rubber-like material separating the inner plate from each of the two outer plates, the inside and outside diameter of both masses of rubber-like material being equal to the inside and outside diameters respectively of the outer metallic discs, the inside disc and one outside disc being scalloped at their outer periphery, said outside disc havingdowels projecting outwardly therefrom, the other outside disc having a circular outer peripheryand being pierced at points aligned with the scallops 0f the other two discs, said other disc having an outside surface uninterrupted by dowels, said masses of rubber-like material being scalloped to correspond to said inside disc and the first named file of this patentz outside I disc.

. I EMIL H. PIRON.

REFERENCES crrEn The following references are of UNITED STATES PATENTS record in the 

